Tick-borne diseases of extensive cattle and sheep Paul Phipps - - PowerPoint PPT Presentation

Tick-borne diseases of extensive cattle and sheep

Paul Phipps Wildlife Zoonoses and Vector Borne Disease Research Group APHA

Phylum: Arthropoda, Class: Arachnida, Order: Parasitiformes Three families: Argasidae (Soft ticks), Ixodidae (Hard ticks), Nutelliedae (1 sp) 3 genera (Ixodes, Haemaphysalis, Dermacentor) described from UK

• Ticks may feed on multiple hosts during their life cycle
• Ticks secrete salivary fluid on attachment which is proteolytic,

immunomodulatory.

• Tick borne pathogens transmitted in salivary fluid during

feeding Diseases transmitted to animals in UK

• Protozoa - babesiosis, theileriosis,
• Bacteria – Tick borne fever, Lyme borreliosis.
• Virus - Louping Ill

Ticks as disease vectors

Ixodes ricinus (sheep, deer, castor bean tick)

• Egg. (Ca 2000 per clutch)

Life cycle

• Larva. Small and large

mammals and birds

• Nymph. Small, large

mammals and birds

• Adult. Large

mammals

• All feeding stages

hatch in late summer/autumn

• Host seeking peaks in

spring and late summer/autumn

• Ticks unable to find

host in Autumn seek host in following spring

• Ca 3 years to

complete life cycle (only 20 days feeding

• n host)
• I. ricinus requires rH

ca 90% to survive off host.

Babesia sp. infecting cattle in UK

• B. divergens (Redwater Fever)
• B. major (non pathogenic ??)
• Intra-erythrocytic protozoan parasite
• B. divergens transmitted by I. ricinus
• B.major transmitted by

Haemaphysalis punctata.

• Infection picked up by feeding female

tick – transovarial transmission to larva via egg then transtadially to nymph and adult

• Infection via sporozoites in the

salivary fluid of feeding tick

Signs and symptoms of clinical babesiosis

• Increased temperature (>40C)
• Pipe stem diarrhoea may be followed by

constipation

• Hammer pulse (visually evident)
• Respiratory distress
• Haemoglobinuria (port wine red urine due rupture
• f the rbcs)
• Anaemia
• Abortion in pregnant cows
• Death (although rare in UK cattle)
• Premunity following recovery (carrier state)

Haemolytic anaemia following

• B. divergens infection

Endemic Stability = Low level of disease Calves below 6months resistant to disease Colostral Ab from carrier dams Continued tick challenge

Tick borne fever: Anaplasma phagocytophilum

• Transmitted by I.ricinus, in UK.
• Symptoms include high fever

>40C, severe loss in milk production

• Infects neutrophils, eosinophils

and later monocytes.

• Immunosupressive - may lead to

Tick pyaemia, pasteurellosis, septicaemic listeriosis, louping ill.

• Abortion storms in naive

animals.

A.phagocytophilum in bovine neutrophil

Louping Ill

Louping ill in the UK (2007)

Species Number of cases Sheep (Ovis aries) 31 Cattle (Bos taurus) 12 Red grouse (Lagopus lagopus scoticus) 67 Hare (Lepus timidus) 17

A Flavivirus, Limited geographical distribution Causes acute encephalomyelitis in sheep Vaccine available for veterinary use Other domestic animals and wildlife affected Transmitted by Ixodes ricinus ticks

Theileriosis of cattle and sheep

Ovine Theileria sp in sheep rbc Theileria sp schizont in lymphocyte

• Transmitted by Haemaphysalis punctata ticks

(Coastal habitats in South East and West Wales) Cattle

• T. mutans described by Brocklesby et al 1972 .

Low pathogenicity. Sheep

• T. ovis – Lewis & Purnell 1981 (Ogmore, South

Wales)

• T. recondita – Alani and Herbert 1988 (Lleyn

peninsular, North wales)

• Low pathogenicity

However……..

Ovine theileriosis UK

• April 2005 mortality associated with heavy infestations of
• H. punctata.
• 60 ewes and their lambs grazing north Kent marshland

25 deaths.

• PM revealed: Oedema of lips, tongue, lungs, froth in
• trachea. Spleen enlarged, kidneys pale, anaemia.
• Anaplasmoid inclusions in Giemsa stained blood smears
• No disease reported since

2012

• 21 blood samples collected from sheep grazing same

pastures

• 16/21 positive by pan-piroplasm PCR, sequencing

revealed T. luwenshuni.

• Same parasite reported as pathogenic in China and

transmitted by Haemaphysalis sp. (Yin et al 2007)

• Is this T. ovis/T recondita previously reported in the

1980s ?

Phipps et al. (2016) Detection of Theileria luwenshuni in sheep from Great Britain. Parasites & Vectors 9:203

• Brugman et al (2015) Parasites

and Vectors, 8(421), 1-8 Molecular species detection, host preferences and detection

• f Myxoma virus in the

Anopheles maculopennis complex in Southern England.

• Xenodiagnosis of viral disease in

mosquitoes collected from Elmleigh Marshes, Isle of Sheppey.

• Blood meal analysis showed that A.

atroparvus and C. annulata (mosquitoes) both fed on cattle

• Theileria orientalis detected by pan-

piroplasm PCR and sequencing – a strain of the organism currently causing well publicised disease

• utbreaks in NZ and Australia
• Is this the T. mutans described by

Brockelsby et al in 1972?

Bovine theileriosis UK

Thank you for your attention!

Paul Phipps, Wildlife Zoonoses and Vector Borne Disease Research Group, Virology Dept APHA.